Image sensor module

ABSTRACT

A image sensor module having a double-sided flexible printing circuit board (FPCB) having a window formed; an image sensor attached on one side of the double-sided FPCB so as to cover the window; and at least one electric part attached on the other side of the double-sided FPCB having the image sensor attached thereto.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. divisional application filed under 35 USC1.53(b) claiming priority benefit of U.S. Ser. No. 11/507,477 filed inthe United States on Aug. 22, 2006, which claims earlier prioritybenefit to Korean Patent Application No. 2005-0077752 filed with theKorea Intellectual Property Office on Aug. 24, 2005, the disclosures ofwhich are incorporated herein by reference.

BACKGROUND

1. Field

The present invention relates to an image sensor module, a method ofmanufacturing the same, and a camera module using the same, in which thesize of the camera module is reduced to thereby strengthencompetitiveness in cost and product.

2. Description of the Related Art

In general, a ceramic package is packaged by a ceramic material so as toprotect a chip such as an IC chip from the outside, and has multiplepins formed outside so as to be fixed to a printed circuit board (PCB).The ceramic package constructed in such a manner serves as a path foremitting heat, protects an IC mounted therein from the externalenvironment, and is sealed so as to endure an external impact. Thereason why ceramic is used as a package is that the ceramic has higherheat conductivity than other materials, is not easily deformed by heat,has a dielectric constant favorable for transmitting signals and lowdielectric loss as an insulating body, and is chemically stable andexcellent in combination with metallic material of wiring pattern.

As a method of packaging an image sensor for camera, there are provideda flip chip chip-on-film (COF) method, a wire bonding chip-on-board(COB) method, a chip scale package (CSP) an the like, among which theCOF and COB methods are widely used.

The COB method is a similar process to that of an existing semiconductorproduction line and has higher productivity than other packagingmethods. However, since wire should be used for the connection with aPCB, the size of a module increases and an additional process is needed.Therefore, a new packaging technique is required to reduce the size ofchip, to enhance heat emission and electrical performance, and toimprove reliability. Accordingly, a COF method has emerged, based onbumps having an external bonding projection.

In the COF method, a space for attaching wire is not needed. Therefore,the area of a package and the height of a lens barrel can be reduced.Further, since a thin film or flexible printed circuit board (FPCB) isused, a reliable package which endures an external impact can bemanufactured and the process thereof is relatively simplified. Moreover,the COF method satisfies such a tendency that signals are processed athigh speed, high density is required, and multiple pins are needed.

The COF method is implemented as chip size wafer-scale packaging.However, the process cost thereof is expensive, and the correspondenceto the due date is unstable. Therefore, the method has a limit as amethod for image sensor.

Further, in a module using a mega-quality sensor to which variousfunctions are added, the miniaturization of module, which has been amerit of the COF method, is not realized any more, because of theone-story structure. The module cannot but be designed to have a largersize than in the COB method.

Currently, a double-sided flexible printed circuit board (FPCB) is usedso that a module can be designed to have a similar size to that in theCOB method, which does not satisfy the miniaturization of module whichis a merit of the COF method. Therefore, since the COB method tends tobe frequently used, the design and process technique for implementingthe miniaturization of module are required.

Then, the conventional image sensor module using the COF method will bedescribed with reference to accompanying drawings, and the problemsthereof will be examined.

FIG. 1 is a cross-sectional view illustrating a camera module includingthe image sensor module according to the related art, and FIG. 2 is aplan view illustrating the image sensor module according to the relatedart. In the drawings, it is shown that multilayer ceramic capacitors 20and the image sensor 18 are attached on one side of a flexible printedcircuit board (FPCB) 16.

As shown in FIG. 1, the camera module including the conventional imagesensor includes a housing 1 having a lens 12 provided in an openingthereof, an IR cut filter 14 which is installed inside the opening ofthe housing 10 provided with the lens 12, and an image sensor modulewhich is installed inside the housing 10 and is composed of the FPCB 16having multiple multilayer ceramic capacitors 20 and the image sensor 18formed on one side thereof. In the image sensor module shown in FIG. 2,a window 16 a for transmitting an image signal to the image sensor 18installed in the opposite side is formed in the FPCB 16, the imagesignal being transmitted through the lens 12 and the IR cut filter 14.At this time, the image sensor 18 serves to process a received imagesignal, and the IR cut filter 14 serves to cut infrared rays incidentfrom the outside. Further, the multilayer ceramic capacitors 20 serve toremove screen noise generated in the camera module.

In the conventional image sensor module having such a construction,however, the image sensor 18 is attached on the same surface as thesurface of the FPCB 16 on which the multilayer ceramic capacitors 20 areinstalled. Therefore, the overall size of the image sensor moduleincreases, which is occupied on the FPCB 16.

In the conventional image sensor module, if the camera module is limitedto a constant size by the request of a user, an active or passiveelement including the multilayer ceramic capacitor 20 should beinevitably removed from the image sensor module in order to design aproduct within the limited size of the camera module. At this time, ifthe multilayer ceramic capacitor 20 is removed from the image sensormodule, screen noise occurs. However, such problems are inevitable inorder to reduce the overall size of the camera module including thehousing.

Furthermore, when the multilayer ceramic capacitors 20 are installed inthe conventional image sensor module in order to remove screen noise,there is a limit in reducing the size of the camera module, because themultilayer ceramic capacitor 20 and the image sensor 18 should beattached on one side of the FPCB 16.

SUMMARY

An advantage of the present invention is that it provides an imagesensor module and a camera module using the image sensor module. In theimage sensor module, an image sensor is disposed on one side of adouble-sided flexible printed circuit board (FPCB) and electric partssuch as multilayer ceramic capacitors are disposed on the other sideopposite to the side where the image sensor is positioned, therebyreducing the size of the camera module.

Another advantage of the invention is that it provides a method ofmanufacturing the image sensor module.

Additional aspects and advantages of the present general inventiveconcept will be set forth in part in the description which follows and,in part, will be obvious from the description, or may be learned bypractice of the general inventive concept.

According to an aspect of the invention, a method of manufacturing animage sensor module includes attaching an image sensor on one side of adouble-sided flexible printing circuit board (FPCB) provided with awindow such that the image sensor module covers the window; and mountingat least one electric part on the other side of the double-sided FPCBhaving the image sensor attached thereto.

As the electric parts, multilayer ceramic capacitors (MLCC) are used. Inmounting the multilayer ceramic capacitors, the multilayer ceramiccapacitors are attached through a hardening process after solder creamis coated on portions where the multilayer ceramic capacitors are to beattached.

In mounting the multilayer ceramic capacitors, an anisotropic conductivefilm (ACF) is inserted between the other side of the double-sided FPCBand the multilayer ceramic capacitors and is then pressed so as toattach the multilayer ceramic capacitors.

In attaching the image sensor, an anisotropic conductive film (ACF) isinserted between the one side of the double-sided FPCB and the imagesensor and is then pressed so as to attach the image sensor.

In attaching the image sensor, non-conductive polymer (NCP) is putbetween the one side of the double-sided FPCB and the image sensor andis then pressurized so as to attach the image sensor.

In attaching the image sensor, an ultrasonic wave is used to attach theimage sensor.

According to another aspect of the invention, an image sensor moduleincludes a double-sided flexible printing circuit board (FPCB) having awindow formed; an image sensor attached on one side of the double-sidedFPCB so as to cover the window; and at least one electric part attachedon the other side of the double-sided FPCB having the image sensorattached thereto.

According to a further aspect of the invention, a camera module includesa housing; a lens section mounted in the housing; an IR cut filtermounted in the housing so as to cut infrared rays from the incidentlight passing through the lens; and an image sensor module composed of adouble-sided flexible printing circuit board (FPCB) in which a windowfor transmitting the incident light passing through the IR cut filter isformed, an image sensor which is attached on one side of thedouble-sided FPCB so as to cover the window; and at least one electricpart which is attached on the other side of the double-sided FPCB havingthe image sensor attached thereto, the image sensor module being coupledto the housing.

The electric parts are mounted so as to be positioned between the windowand the outer circumference of the image sensor.

The electric parts includes at least one multilayer ceramic capacitor(MLCC).

The image sensor has multiple electrode pads formed on the surfacethereof which is attached to the one side of the double-sided FPCB, andbumps are formed in the electrode pads.

The bump is composed of any one of a stud-type bump, a non-electrolyticbump, and an electrolytic bump.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the present generalinventive concept will become apparent and more readily appreciated fromthe following description of the embodiments, taken in conjunction withthe accompanying drawings of which:

FIG. 1 is a sectional view illustrating an image sensor according to therelated art;

FIG. 2 is a plan view illustrating the image sensor according to therelated art;

FIG. 3 is an exploded perspective view illustrating a camera moduleincluding an image sensor module according to the present invention;

FIG. 4 is a sectional view illustrating the camera module including theimage sensor module according to the invention; and

FIGS. 5A and 5B are plan views illustrating the image sensor moduleaccording to the invention, respectively seen from one side and theother side thereof.

DETAILED DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to the embodiments of the presentgeneral inventive concept, examples of which are illustrated in theaccompanying drawings, wherein like reference numerals refer to the likeelements throughout. The embodiments are described below in order toexplain the present general inventive concept by referring to thefigures.

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings.

[Image Sensor Module and Camera Module]

FIG. 3 is an exploded perspective view illustrating a camera moduleincluding an image sensor module according to the present invention,FIG. 4 is a cross-sectional view illustrating the camera moduleincluding the image sensor module according to the invention, and FIGS.5A and 5B are plan views illustrating the image sensor module accordingto the invention, respectively seen from one side and the other side.

As shown in FIGS. 3 and 4, the camera module according to the inventionincludes a housing 110 having a lens 120 provided in an opening thereof,an IR cut filter 140 which is installed inside the opening of thehousing 110 having the lens 120, and the image sensor module which iscoupled so as to be disposed in the housing 110. The lens 120, the IRcut filter 140, and the image sensor 180 are positioned on a straightline by reference to the axis of incident light.

The image sensor module includes a double-sided FPCB (Flexible PrintingCircuit Board) 160, an image sensor 180 attached on the lower surface ofthe double-sided FPCB 160, and at least one electric part 200 which isattached on the upper surface opposite to the surface of thedouble-sided FPCB 160 on which the image sensor 180 is positioned.

In the double-sided FPCB 160, a window 160 a is formed, through whichthe light incident on the lens 120 and the IR cut filter 140 istransmitted to the image sensor 180. Then, the image sensor 180 convertsthe light into an image signal.

The image sensor 180, which processes the image signal received throughthe lens 120 and the IR cut filter 140, has a plurality of electrodepads (not shown) formed on the surface attached to one side of thedouble-sided FPCB 160, each of the electrode pads having a bump. Thebump can be composed of any one of a stud-type bump, a non-electrolyticbump, and an electrolytic bump, among which the stud-type bump ispreferably used.

The IR cut filter 140 serves to cut infrared rays incident from theoutside.

In the electric parts 200, at least one multilayer ceramic capacitor(MLCC) is included. Additionally, other electric parts such as resistor,diode, transistor and the like can be included. Here, the multilayerceramic capacitor (MLCC) serves to remove screen noise occurring in acamera module, and other electric parts can be used to improve a qualityof the camera module.

Meanwhile, a specific relationship between the electric part 200 and theimage sensor 180, which are disposed in the double-sided FPCB 160, isshown in FIGS. 5A and 5B. FIG. 5A is a plan view illustrating the imagesensor module according to the invention, seen from the inside of thehousing. FIG. 5B is a plan view illustrating the image sensor moduleaccording to the invention, seen from the outside of the housing. Aroundthe window 160 a formed in the double-sided FPCB 160, the electric parts200 including multilayer ceramic capacitors are mounted on the uppersurface of the double-sided FPCB 160, and the image sensor 180 isattached on the lower surface thereof, as described in FIGS. 5A and 5B.Preferably, the electric parts 200 are mounted so as to be positionedinside the surface where the image sensor 180 is attached, that is,between the window 160 a and the outer circumference of the image sensor180. Accordingly, compared with the conventional image sensor module inwhich the image sensor is attached on the same surface as the surface ofthe FPCB on which multilayer ceramic capacitors are installed, the imagesensor module can be designed so that the overall size thereof isreduced. As an example, the conventional image sensor module has a sizeof 6.6×6.6. According to the invention, however, the image sensor modulecan be designed so as to have a size of 6.0×6.0, which makes it possibleto reduce the overall size of the camera module. Further, since the sizeof the image sensor module according to the invention can be reduced,parts such as chip register for quality improvement can be mounted onthe surplus space, in addition to the multilayer ceramic capacitor.

[Method of Manufacturing Image Sensor Module]

A method of manufacturing an image sensor module according to thepresent invention, that is, a method of attaching the image sensor 180and the multilayer ceramic capacitors 200 on one side and the other sideof the double-sided FPCB 160, respectively, is as follows.

First, as a method of attaching the image sensor 180 on one side of thedouble-sided FPCB 160, the following methods can be used. A first methodis where an anisotropic conductive film (ACF) is inserted between onesurface of the double-sided FPCB 160 and the image sensor 180 and isthen pressed so as to attach the image sensor 180. A second method iswhere non-conductive polymer (NCP) is inserted between one surface ofthe double-sided FPCB 160 and the image sensor 180 and is thenpressurized so as to attach the image sensor 180. A third method iswhere an ultrasonic wave is used to attached the image sensor 180.

Next, as a method of attaching the multilayer ceramic capacitors 200 onthe other side of the double-sided FPCB 160, the following methods canbe used. A first method is where solder cream is coated on portionswhere the multilayer ceramic capacitors 200 are to be attached and ahardening process is performed so as to attach the image sensor 180. Asecond method is where an anisotropic conductive film (ACF) is insertedbetween the other side of the double-sided FPCB 160 and the multilayerceramic capacitors 200 and is then pressed so as to attach the imagesensor 180. Here, although all the methods can be used in the invention,the method using solder cream is preferably used.

According to the image sensor module, the method of manufacturing thesame, and the camera module using the image sensor module, the imagesensor is disposed on one side of the double-sided FPCB, and theelectric parts such as multilayer ceramic capacitors are disposed on theother side opposite to the one side on which the image sensor ispositioned, which makes it possible to reduce the size of the cameramodule.

Since the camera module can be miniaturized, it is possible tostrengthen competitiveness in cost and product.

In the related art where the multilayer ceramic capacitors and the imagesensor are disposed in the same direction, epoxy or the like is moldedso as to entirely cover the multilayer ceramic capacitors and the imagesensor. In the present invention, however, the multilayer ceramiccapacitors are disposed in the opposite side to the side where the imagesensor is attached. Therefore, molding may be performed so that only theimage sensor is covered, which makes it possible to reduce an amount ofmolding material.

Furthermore, in the conventional image sensor module, only themultilayer ceramic capacitors for removing screen noise can be mountedbecause of the narrow space. In the present invention, however, otherelectric parts for improving a quality can be mounted because the spaceis effectively utilized.

Although a few embodiments of the present general inventive concept havebeen shown and described, it will be appreciated by those skilled in theart that changes may be made in these embodiments without departing fromthe principles and spirit of the general inventive concept, the scope ofwhich is defined in the appended claims and their equivalents.

1. An image sensor module comprising: a double-sided flexible printingcircuit board (FPCB) having a window formed; an image sensor attached onone side of the double-sided FPCB so as to cover the window; and atleast one electric part attached on the other side of the double-sidedFPCB having the image sensor attached thereto.
 2. The image sensormodule according to claim 1, wherein the electric parts are mounted soas to be positioned between the window and the outer circumference ofthe image sensor.
 3. The image sensor module according to claim 1,wherein the electric parts include at least one multilayer ceramiccapacitor (MLCC).
 4. The image sensor module according to claim 1,wherein the image sensor has multiple electrode pads formed on thesurface thereof which is attached to the one side of the double-sidedFPCB, and bumps are formed in the electrode pads.
 5. The image sensormodule according to claim 4, wherein the bump is composed of any one ofa stud-type bump, a non-electrolytic bump, and an electrolytic bump.